Erosion, Corrosion, and Fatigue Prevention for High-Pressure Pumps

ABSTRACT

Disclosed are methods of enhancing resistance to erosion, corrosion, wear and tear, and fatigue in high-pressure pumps. One method includes providing a fluid end that comprises a body defining a pressure chamber in fluid communication with a plunger bore having a plunger reciprocably disposed therein, a suction valve pocket defined in the body and having inlet valve assembly arranged therein that includes a suction valve and a suction valve seat, and a discharge valve pocket defined in the body and having a discharge valve assembly arranged therein that includes a discharge valve and a discharge valve seat, and applying a wear-resistant substance directly to a surface of at least one of the pressure chamber, the plunger, the suction valve pocket, the suction valve, the suction valve seat, the discharge valve, and the discharge seat.

BACKGROUND

The present application is related to high-pressure pumps and, more particularly, to methods of enhancing resistance to erosion, corrosion, wear and tear, and fatigue in high-pressure pumps.

It is common practice in the oil and gas industry to employ high-pressure positive displacement or reciprocating pumps in a variety of field operations relating to the exploration, preparation, and extraction of hydrocarbons. For example, such pumps are often used in cementing a wellbore as part of a completion operation. High-pressure pumps are also used in acidizing and hydraulically fracturing subterranean formation during wellbore treatment operations. The fluid end of such pumps is the portion of the pump where a fluid is drawn in via a suction valve and subsequently discharged under pressure. Within the fluid end of a reciprocating high pressure pump, a plunger or piston compresses the fluid and pushes it under pressure through a discharge valve. The discharge valve is typically designed to open when the pressure on its bottom side is higher than the pressure on its top side thereof.

Such pumps are frequently used in pumping two-phase slurries where solid particles are suspended in a liquid (e.g., proppant suspended in a fracturing fluid). At least one problem with pumping such two-phase slurries is that the slurry oftentimes makes the fluid end susceptible to damage in the form of erosion, corrosion, wear and tear, and fatigue. Damage to high-pressure pumps can also result from pumping highly-corrosive fluids, such as acids or the like. Ultimately, such damage can result in bore enlargement or cracking of the fluid end which may decrease efficiencies or otherwise require the pump to be shut down and repaired or replaced altogether. As can be appreciated, this may prove to be quite costly and time-consuming. Accordingly, it is desirable to provide a fluid end for a high-pressure pump with enhanced resistance to erosion, corrosion, wear and tear, and fatigue.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.

FIG. 1 is an isometric view of an exemplary high-pressure pump that may employ one or more principles of the present disclosure.

FIG. 2 is an isometric view of an exemplary fluid end of the high-pressure pump of FIG. 1.

FIG. 3 illustrates a cross-sectional view of the fluid end of FIG. 2.

DETAILED DESCRIPTION

The present application is related to high-pressure pumps and, more particularly, to methods of enhancing resistance to erosion, corrosion, wear and tear, and fatigue in high-pressure pumps.

The present disclosure describes treating various internal portions, surfaces, parts, and/or components (collectively “fluid end internals”) of a high-pressure pump fluid end with a wear-resistant substance in order to reduce the likelihood of failure due to erosion, corrosion, and wear/tear. The wear-resistant substance may be applied directly to the surfaces of the fluid end internals and, if needed, may be re-applied on subsequent occasions to prolong the valuable life of the high-pressure pump. The wear-resistant substance may be applied by either thermal spraying or sintering processes and, if desired, the treated surfaces may subsequently be machined to engineering tolerances. Treating the fluid end internals with the wear-resistant substances may prove advantageous in reducing maintenance costs for high-pressure pumps. Treated surfaces may further be repairable using the wear-resistant substances, thereby making the fluid end of the high-pressure pump reusable. Accordingly, the principles and embodiments described below will save well operators time and expense in maintaining fluid ends for high-pressure pumps.

Referring to FIG. 1, illustrated is an exemplary high-pressure pump 100 that may employ one or more principles of the present disclosure. As illustrated, the pump 100 includes a power end 102 that houses a series of gears and rods (not shown), and a fluid end 104 operatively coupled to the power end 102. While the illustrated pump 100 is depicted as a reciprocating pump, the principles of the present disclosure are equally applicable to other types of positive-displacement pumps, such as centrifugal pumps, gear pumps, screw pumps, rotary vane pumps and the like. The pump 100 may be used in a variety of field operations relating to oil and gas wells, such as acidizing, hydraulic fracturing, cementing, and the like. Other types of pumps, however, such as water pumps, mud pumps, delta pumps, etc., may equally implement embodiments of the present disclosure.

As used herein, the term “high-pressure” as used to characterize the pumps described herein, refers to fluid pumping pressures ranging between about 1000 psi to about 20,000 psi, and can be as high as 35,000 psi.

The pump 100 is illustrated as a quintuplex pump where the fluid end 104 provides or otherwise comprises five fluid pumping chambers, shown as chambers 106 a, 106 b, 106 c, 106 d, and 106 e. Those skilled in the art, however, will readily appreciate that the embodiments disclosed herein may equally be employed on high-pressure pumps having more or less than five fluid pumping chambers 106 a-e (including one), without departing from the scope of the disclosure. The fluid end 104 includes an inlet 108 that feeds a working fluid to each fluid pumping chamber 106 a-e via a suction manifold 110 fluidly coupled thereto. Exemplary working fluids that may be used in the pump 100 may include, but are not limited, to fracturing fluids, fracturing slurries (i.e., solid particles suspended in a fracturing fluid), acids, cements, drilling fluids, and the like.

The fluid end 104 also provides or otherwise defines an outlet 112 fluidly coupled to each fluid pumping chamber 106 a-e. In operation, the fluid pumping chambers 106 a-e pressurize the working fluid, convey the pressurized working fluid to the outlet 112, and the outlet 112 conveys the pressurized working fluid downstream to a wellbore, for example.

Referring now to FIG. 2, with continued reference to FIG. 1, illustrated is an isometric view of an exemplary fluid pumping chamber 200. More specifically, illustrated is an isometric view of the first fluid pumping chamber 106 a of the fluid end 104 of FIG. 1. While shown in FIG. 2 as being separable from the remaining fluid pumping chambers of the fluid end 104 (FIG. 1), those skilled in the art will readily recognize that the fluid pumping chamber 200 may alternatively be non-separable and otherwise form part of a single, monoblock fluid end, without departing from the scope of the disclosure. Accordingly, the fluid pumping chamber 200 will be referred to herein as a fluid end 200, with the understanding that the fluid end 200 may include one or several fluid pumping chambers.

As depicted, the fluid end 200 is a side-discharge fluid end for a reciprocating pump. Those skilled in the art, however, will readily appreciate that the principles of the present disclosure may equally be applied to a front-discharge fluid end, or any other types of fluid ends, without departing from the scope of the disclosure. The fluid end 200 provides a housing or body 202 that defines one or more holes 204 therein for coupling the fluid end 200 to the power end 102 (FIG. 2). The outlet 112 to the fluid end 200 is also depicted.

Referring to FIG. 3, with continued reference to FIG. 2, illustrated is a cross-sectional view of the fluid end 200 of FIG. 2. The body 202 of the fluid end 200 defines a plunger bore 302 and a piston or plunger 304 may be reciprocably disposed in the plunger bore 302. One or more seals 306 may be arranged about the plunger 304 within the plunger bore 302 to provide sealing engagement between the body 202 and the plunger 304. During operation, as the plunger 304 reciprocates within the plunger bore 302, it simultaneously extends partially into the interior or pressure chamber 308 of the fluid end 200.

The body 202 may further define a suction valve pocket 310 and a discharge valve pocket 312, each of which are in fluid communication with the bore 302. The suction valve pocket 310 has an inlet valve assembly 314 disposed therein, and the inlet valve assembly 314 generally includes a suction valve 316 biased by a spring 318 against a suction valve seat 320. In some embodiments, as illustrated, the discharge valve pocket 312 may be axially aligned with the plunger bore 302 along a longitudinal axis 322 of the fluid end 200. In other embodiments, however, the discharge valve pocket 312 may be axially aligned with the suction valve pocket 310, without departing from the scope of the disclosure. The discharge valve pocket 312 may be generally defined by a discharge bore 324 having an outwardly facing shoulder 326 at one end thereof. In some cases, the discharge bore 324 may simply be an extension of the plunger bore 302, without departing from the scope of the disclosure.

A discharge valve assembly 328 is arranged within the discharge valve pocket 312 and generally adjacent a valve seat 330 that extends a short distance into the discharge bore 324. One or more sealing elements 332 may be used to provide a sealing engagement between the valve seat 330 and the body 202 adjacent the shoulder 326. A discharge valve 334 is positioned adjacent the valve seat 330 and one or more sealing means, such as a valve insert 336, provides a sealing engagement between the discharge valve 334 and valve seat 330 when the discharge valve assembly 328 is in the closed position, as shown in FIG. 3.

The discharge valve 334 may have an elongated guide portion 338 arranged within a sleeve-like valve stem 340. The valve stem 340 may be slidably supported in a sleeve-like bushing retainer 342. The bushing retainer 342 defines an annular shoulder 344, and a discharge valve spring 346 is disposed between the shoulder 344 and the discharge valve 334, thereby providing a biasing means for biasing the discharge valve 334 toward its closed position. A discharge cage 348 is disposed within the discharge bore 324 and generally surrounds the discharge valve 334, the bushing retainer 324, and the spring 346. An opening 350 may be defined in the discharge cage 348 and configured to provide a fluid conduit to the outlet 112 (FIG. 2) of the fluid end 200.

A plug assembly 352 may be arranged at the distal end of the discharge valve pocket 312. The plug assembly 352 may generally include a plug 354 having a stem 356 that extends longitudinally therefrom. A cap or cover 358 is threaded into the discharge bore 324 and provides an inner bore 360 through which the stem 356 extends. The plug 354 serves to seal the distal end of the discharge valve pocket 312 for operation.

In exemplary operation of the fluid end 200, fluid enters the pressure chamber 308 of the fluid end 200 via the inlet valve assembly 314 arranged in the suction valve pocket 310. The plunger 304 is powered to reciprocate toward and away from the discharge valve pocket 312 in order to pressurize the incoming fluid. In this manner, the plunger 304 affects high and low pressures on the discharge valve pocket 312. For example, as the plunger 304 is thrust toward the discharge valve pocket 312, the pressure within the discharge valve pocket 312 is increased.

At some point, the pressure increase will be sufficient to open the discharge valve 334 and thereby allow the release of the pressurized fluid from the discharge valve pocket 312, through the opening 350 defined in the discharge cage 348, and out of the pump body 202. The amount of pressure required to open the discharge valve 334 may be determined, at least in part, by the spring 338, which maintains the discharge valve 334 in its closed position until the requisite pressure is achieved in the discharge valve pocket 312.

The plunger 304 may also affect a low pressure on the discharge valve pocket 312. That is, as the plunger 304 retracts away from its advanced discharge position near the discharge valve pocket 312, the pressure therein will decrease. As the pressure within the discharge valve pocket 312 decreases, the discharge valve 334 will close, thereby returning the discharge valve pocket 312 to a sealed state. As the plunger 304 continues to move away from the discharge valve pocket 312, the pressure therein will continue to drop, and eventually a low or negative pressure will be achieved within the discharge valve pocket 312.

Similar to the action of the discharge valve 334 described above, the pressure decrease will eventually be sufficient to affect an opening of the suction valve 316 arranged within the inlet valve assembly 314. Opening the suction valve 316 allows the uptake of fluid into the discharge valve pocket 312 from a fluid intake channel 362 adjacent thereto. The amount of pressure required to open the suction valve 316 may be determined by an intake mechanism, such as the spring 318, that keeps the suction valve 316 in its closed position until the requisite low pressure is achieved in the discharge valve pocket 312.

Accordingly, the reciprocating or cycling motion of the plunger 304 toward and away from the discharge valve pocket 312 within the pressure chamber 308 of the fluid end 200 controls the pressure therein. The suction and discharge valves 316, 334 respond accordingly in order to dispense fluid from the discharge valve pocket 312, through the opening 350 defined in the discharge cage 348, and out of the pump body 202 at high pressure. The discharged fluid is then replaced with fluid from within the fluid intake channel 362.

As will be appreciated by those skilled in the art, the continued cycling of the plunger 304 into and out of the pressure chamber 308 of the fluid end 200, and the accompanied fluctuations between positive and negative pressure experienced by the inner surfaces of the fluid end 200, makes the fluid end 200 susceptible to failure. For instance, such sustained and cyclic loading motion may result in the erosion, corrosion, and wear and tear of various internal metal surfaces of the fluid end 200. Detrimental erosion, corrosion, and wear and tear may also be the result of fluid cavitation within the fluid end 200, solids suspended within the fluids pumped through the fluid end 200, and pumping various types of corrosive fluids will lead to corrosion (e.g., acids).

According to the present disclosure, various internal portions, surfaces, parts, and/or components (collectively “fluid end internals”) of the fluid end 200 that may be exposed to the high pressure conditions of the pump 100 (FIG. 1) may be treated in order to reduce the likelihood of failure due to erosion, corrosion, and wear and tear. If not properly treated, as disclosed herein, such fluid end internals may end up corroding, eroding, cracking, and, ultimately, failing.

While each internal portion, surface, part, and/or component of the fluid end 200 may be susceptible to erosion, corrosion, and wear and tear, some fluid end internals are more susceptible than others due to their arrangement and resulting angle of impingement of the pumped working fluids. The fluid end internals of the fluid end 200 that may be most susceptible to erosion, corrosion, and wear and tear include, but are not limited to, the inner bore 360 of the cover 358, all surfaces of the cage 348, all surfaces of the discharge valve 334, all surfaces of the discharge valve seat 330, surfaces of the pressure chamber 308 of the fluid end 200, the inner surfaces of the suction valve pocket 310, all surfaces of the suction valve 316, all surfaces of the suction valve seat 320, the outer surfaces of the plunger 304, valve inserts, valve bodies, valve guides, and the packing and fluid end sections.

As disclosed herein, the fluid end internals susceptible to erosion, corrosion, and wear and tear may be treated or otherwise coated with a wear-resistant substance (i.e., chemical, compound, material, etc.) prior to being placed in long-term operation in a high-pressure pump or at any time during the life of the fluid end 200. As used herein, the term “wear-resistant substance” refers to substances that generally resist or are otherwise able to withstand wear and tear or erosion/corrosion. A wear-resistant substance, however, also refers to substances that generally resist or are otherwise able to withstand corrosion when applied to a metal surface. The wear-resistant substance applied to the surfaces of the fluid end internals may produce compression stress, which may enhance the fatigue life of the fluid end internals. It has been found that the direct application of specific wear-resistant substances to surfaces of the fluid end internals can provide effective enhancement of the service lifetime of high-pressure pumps, thereby making their utilization much more practical and cost effective.

Suitable wear-resistant substances that may be directly applied to the fluid end internals to prevent erosion, corrosion, and wear and tear include, but are not limited to, tungsten carbide-cobalt, tungsten carbide, cobalt, cobalt alloys, thermal barrier coating of zirconium, yittria-stabilized zirconia, aluminium, zinc, molybdenum, molybdenum and molybdenum blend coatings, zinc chromate, chromium, chromium carbide, nickel chromium, colmonoy 6 (NiCrSiB), fused self-fluxing alloys, aluminum bronze, copper nickel indium, and nickel alloys.

The selection of which wear-resistant substance to apply to a particular fluid end internal may be dependent on the severity and type of erosion common to that fluid end internal. For example, for fluid end internals that are more susceptible to solid impingement erosion at a shallow angle of attack (e.g., erosion similar to that of abrasion), a high-hardness wear-resistant coating would be recommended.

One method of applying the wear-resistant substances directly to the surfaces of the fluid end internals is through the family of processes known collectively as thermal spraying. Suitable thermal spraying processes that may be used include, but are not limited to, wire arc spraying, flame spraying, plasma spraying (e.g., induction plasma spraying, vacuum plasma spraying, etc.), supersonic spraying, controlled atmosphere plasma spraying, low pressure plasma spraying, cold spraying, warm spraying, underwater plasma spraying, combustion wire thermal spraying, combustion powder thermal spraying, detonation thermal spraying, and high velocity oxygen fuel (HVOF) thermal spraying. Advantageously, such thermal spraying techniques result in coatings that contain interconnected porosity that may be fine or coarse, depending on the process and process parameters used.

Another method of applying the wear-resistant substances directly to the surfaces of the fluid end internals is through sintering processes. In the sintering process, one or more wear-resistant substances in powder form is directly applied to the surface of a fluid end internal and then the fluid end internal is heat-treated to form a solid, wear and corrosion-resistant surface on the fluid end internal. Suitable sintering processes that may be used include, but are not limited to, ceramic sintering (e.g., glass, alumina, zirconia, silica, magnesia, lime, beryllium oxide and ferric oxide), metallic powder sintering, liquid phase sintering, electric current sintering, spark plasma sintering, and pressure-less sintering. For wear-resistant substances that have high melting points (e.g., molybdenum, tungsten, rhenium, tantalum, osmium, carbon, etc.), sintering may be one of the few viable manufacturing processes for applying the wear-resistant substance directly to the surfaces of the fluid end internals.

If needed, surfaces of fluid end internals that have been coated with a wear-resistant substance by either thermal spraying or sintering may be subsequently machined so as to maintain acceptable engineering tolerances. As will be appreciated, sintering and thermal spraying, with subsequent re-working or machining, can produce a great range of material properties that work against erosion, corrosion, wear/tear, and fatigue. Moreover, sintering and thermal spraying significantly affects microstructure and mechanical properties of the surfaces and therefore are workable manufacturing processes that help remove or minimize most material basis issues common to high-pressure pumps.

In some embodiments, fluid end internals may be treated with the wear-resistant substance at multiple times throughout the life of the fluid end. For example, the wear-resistance substance may be re-applied to the fluid end internals on a periodic basis or when internal fatigue issues become evident in the fluid internal. This may prove advantageous in maintaining the high-pressure pumping equipment in proper working order and otherwise prevent long-term damage or failure.

Embodiments disclosed herein include:

A. A fluid end for a high-pressure pump. The fluid end includes a body defining a pressure chamber in fluid communication with a plunger bore having a reciprocating plunger disposed therein, a suction valve pocket defined in the body and in fluid communication with the pressure chamber, the suction valve pocket having inlet valve assembly arranged therein that includes a suction valve and a suction valve seat, a discharge valve pocket defined in the body and in fluid communication with the pressure chamber, the discharge valve pocket having a discharge valve assembly arranged therein that includes a discharge valve and a discharge valve seat, and a wear-resistant substance applied directly to a surface of at least one of the pressure chamber, the plunger, the suction valve pocket, the suction valve, the suction valve seat, the discharge valve, and the discharge seat.

B. A method that includes providing a fluid end that comprises a body defining a pressure chamber in fluid communication with a plunger bore having a reciprocating plunger disposed therein, a suction valve pocket defined in the body and in fluid communication with the pressure chamber, the suction valve pocket having inlet valve assembly arranged therein that includes a suction valve and a suction valve seat, and a discharge valve pocket defined in the body and in fluid communication with the pressure chamber, the discharge valve pocket having a discharge valve assembly arranged therein that includes a discharge valve and a discharge valve seat. The method also includes applying a wear-resistant substance directly to a surface of at least one of the pressure chamber, the plunger, the suction valve pocket, the suction valve, the suction valve seat, the discharge valve, and the discharge seat.

Each of embodiments A and B may have one or more of the following additional elements in any combination: Element 1: wherein the high pressure pump is a positive-displacement pump selected from the group consisting of a reciprocating pump, a centrifugal pump, a gear pump, a screw pump, and a rotary vane pump. Element 2: wherein the plunger bore and the discharge valve pocket are axially aligned. Element 3: further comprising a discharge cage arranged within the discharge valve pocket, the wear-resistant substance also being applied directly to surfaces of the discharge cage. Element 4: further comprising a plug assembly arranged at a distal end of the discharge valve pocket and having a cover that defines an inner bore, wherein the wear-resistant substance is further applied directly to surfaces of the inner bore. Element 5: wherein the wear-resistant substance is a substance selected from the group consisting of tungsten carbide-cobalt, tungsten carbide, cobalt, cobalt alloys, thermal barrier coating of zirconium, yittria-stabilized zirconia, aluminium, zinc, molybdenum, molybdenum and molybdenum blend coatings, zinc chromate, chromium, chromium carbide, nickel chromium, colmonoy 6 (NiCrSiB), fused self-fluxing alloys, aluminum bronze, copper nickel indium, and nickel alloys. Element 6: wherein the wear-resistant substance is applied to the surface by a thermal spraying process. Element 7: wherein the thermal spraying process is at least one of wire arc spraying, flame spraying, plasma spraying, supersonic spraying, controlled atmosphere plasma spraying, low pressure plasma spraying, cold spraying, warm spraying, underwater plasma spraying, combustion wire thermal spraying, combustion powder thermal spraying, detonation thermal spraying, and high velocity oxygen fuel thermal spraying. Element 8: wherein the wear-resistant substance is applied to the surface by a sintering process. Element 9: wherein the sintering process is at least one of ceramic sintering, metallic powder sintering, liquid phase sintering, electric current sintering, spark plasma sintering, and pressure-less sintering.

Element 10: wherein the fluid end further comprises a discharge cage arranged within the discharge valve pocket, the method further comprising applying the wear-resistant substance directly to a surface of the discharge cage. Element 11: wherein the fluid end further comprises a plug assembly arranged at a distal end of the discharge valve pocket and having a cover that defines an inner bore, the method further comprising applying the wear-resistant substance directly to a surface of the inner bore. Element 12: wherein applying the wear-resistant substance comprises thermally spraying the wear-resistant substance directly on the surface. Element 13: wherein thermally spraying is accomplished by at least one of wire arc spraying, flame spraying, plasma spraying, supersonic spraying, controlled atmosphere plasma spraying, low pressure plasma spraying, cold spraying, warm spraying, underwater plasma spraying, combustion wire thermal spraying, combustion powder thermal spraying, detonation thermal spraying, and high velocity oxygen fuel thermal spraying. Element 14: wherein applying the wear-resistant substance comprises sintering the wear-resistant substance directly on the surface. Element 15: wherein sintering the wear-resistant substance is accomplished by at least one of ceramic sintering, metallic powder sintering, liquid phase sintering, electric current sintering, spark plasma sintering, and pressure-less sintering. Element 17: further comprising machining the wear-resistant substance applied to the surface. Element 18: further comprising periodically re-applying the wear-resistant substance to the surface.

Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” does not require selection of at least one item; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. 

1. A fluid end for a high-pressure pump, comprising: a body defining a pressure chamber in fluid communication with a plunger bore having a reciprocating plunger disposed therein; a suction valve pocket defined in the body and in fluid communication with the pressure chamber, the suction valve pocket having inlet valve assembly arranged therein that includes a suction valve and a suction valve seat; a discharge valve pocket defined in the body and in fluid communication with the pressure chamber, the discharge valve pocket having a discharge valve assembly arranged therein that includes a discharge valve and a discharge valve seat; and a wear-resistant substance applied directly to a surface of at least one of the pressure chamber, the plunger, the suction valve pocket, the suction valve, the suction valve seat, the discharge valve, and the discharge seat, wherein a discharge cage is arranged within the discharge valve pocket and the wear-resistant substance is applied directly to surfaces of the discharge cage.
 2. The fluid end of claim 1, wherein the high pressure pump is a positive-displacement pump selected from the group consisting of a reciprocating pump, a centrifugal pump, a gear pump, a screw pump, and a rotary vane pump.
 3. The fluid end of claim 1, wherein the plunger bore and the discharge valve pocket are axially aligned.
 4. (canceled)
 5. The fluid end of claim 1, further comprising a plug assembly arranged at a distal end of the discharge valve pocket and having a cover that 3 Preliminary Amendment defines an inner bore, wherein the wear-resistant substance is further applied directly to surfaces of the inner bore.
 6. The fluid end of claim 1, wherein the wear-resistant substance is a substance selected from the group consisting of tungsten carbide-cobalt, tungsten carbide, cobalt, cobalt alloys, thermal barrier coating of zirconium, yittria-stabilized zirconia, aluminium, zinc, molybdenum, molybdenum and molybdenum blend coatings, zinc chromate, chromium, chromium carbide, nickel chromium, colmonoy 6 (NiCrSiB), fused self-fluxing alloys, aluminum bronze, copper nickel indium, and nickel alloys.
 7. The fluid end of claim 1, wherein the wear-resistant substance is applied to the surface by a thermal spraying process.
 8. The fluid end of claim 7, wherein the thermal spraying process is at least one of wire arc spraying, flame spraying, plasma spraying, supersonic spraying, controlled atmosphere plasma spraying, low pressure plasma spraying, cold spraying, warm spraying, underwater plasma spraying, combustion wire thermal spraying, combustion powder thermal spraying, detonation thermal spraying, and high velocity oxygen fuel thermal spraying.
 9. The fluid end of claim 1, wherein the wear-resistant substance is applied to the surface by a sintering process.
 10. The fluid end of claim 9, wherein the sintering process is at least one of ceramic sintering, metallic powder sintering, liquid phase sintering, electric current sintering, spark plasma sintering, and pressure-less sintering.
 11. A method, comprising: providing a fluid end that comprises: a body defining a pressure chamber in fluid communication with a plunger bore having a reciprocating plunger disposed therein; a suction valve pocket defined in the body and in fluid communication with the pressure chamber, the suction valve pocket having inlet valve assembly arranged therein that includes a suction valve and a suction valve seat; and a discharge valve pocket defined in the body and in fluid communication with the pressure chamber, the discharge valve pocket having a discharge valve assembly arranged therein that includes a discharge valve and a discharge valve seat; a discharge cage arranged within the discharge valve pocket; applying a wear-resistant substance directly to a surface of at least one of the pressure chamber, the plunger, the suction valve pocket, the suction valve, the suction valve seat, the discharge valve, and the discharge seat; and applying the wear-resistant substance directly to a surface of the discharge cage.
 12. (canceled)
 13. The method of claim 11, wherein the fluid end further comprises a plug assembly arranged at a distal end of the discharge valve pocket and having a cover that defines an inner bore, the method further comprising applying the wear-resistant substance directly to a surface of the inner bore.
 14. The method of claim 11, wherein applying the wear-resistant substance comprises thermally spraying the wear-resistant substance directly on the surface.
 15. The method of claim 14, wherein thermally spraying is accomplished by at least one of wire arc spraying, flame spraying, plasma spraying, supersonic spraying, controlled atmosphere plasma spraying, low pressure plasma spraying, cold spraying, warm spraying, underwater plasma spraying, combustion wire thermal spraying, combustion powder thermal spraying, detonation thermal spraying, and high velocity oxygen fuel thermal spraying.
 16. The method of claim 11, wherein applying the wear-resistant substance comprises sintering the wear-resistant substance directly on the surface.
 17. The method of claim 16, wherein sintering the wear-resistant substance is accomplished by at least one of ceramic sintering, metallic powder sintering, liquid phase sintering, electric current sintering, spark plasma sintering, and pressure-less sintering.
 18. The method of claim 11, further comprising machining the wear-resistant substance applied to the surface.
 19. The method of claim 11, further comprising periodically re-applying the wear-resistant substance to the surface.
 20. The method of claim 11, wherein the wear-resistant substance is a substance selected from the group consisting of tungsten carbide-cobalt, tungsten carbide, cobalt, cobalt alloys, thermal barrier coating of zirconium, yittria-stabilized zirconia, aluminium, zinc, molybdenum, molybdenum and molybdenum blend coatings, zinc chromate, chromium, chromium carbide, nickel chromium, colmonoy 6 (NiCrSiB), fused self-fluxing alloys, aluminum bronze, copper nickel indium, and nickel alloys. 